It comes as late-night TV host Jimmy Kimmel jokingly revealed the "first photo" of the twins.

"They still actually haven't confirmed the happy news officially, but that's not particularly unusual," he said.

"They did this with their daughter, Blue Ivy, too. They waited years before showing their wedding photos. And to this day, no one knows what happened to the fourth member of Destiny's Child. She's just gone."

Kimmel then unveiled an "exclusive photo" of the newborns - an old picture of President Donald Trump's two sons, Eric and Donald Jr.